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| My First Unimog Experience |
(1) As with most of my projects, I start out on one thing and it generates
several more related projects. My initial goal was replacing the manual fuel
selector valve with a Pollak® 12V 3 port electric motorized selector valve.
I bought the kit from
www.wireconnections.com/ - cost was about $45.
JC Whitney wanted $58 plus shipping. There may be other vendors, but I
was satisfied with Wire Connections' price. The valve switches between two tanks
as well as two electric fuel pumps and two tank senders. I may try to add another
sender in the front tank later on (see, another project). Electric pumps are
way down on my list of projects.
Pollak® strongly recommends filtering each incoming line to prevent gunk
from jamming the valves in the unit, this generated another project too, see
(6) below. See a picture of the motorized valve
here ,work still in progress as of Aug. 15-02. The valve is 12V but I'll
place a dropping resistor in the 24V lead. I figure a 50 Ohm, 4 Watt should
do it. The motorized switch only draws current for a fraction of a second while
it operates. A solenoid valve is always "on", drawing current the whole time
and getting warm in the process. Either one need good filters before the valve.
(2) I first though about cutting the stock lines and inserting two filters and
motorized valve. After some thought I realized it would take about 10 or 12
clamps for the job depending on how I rigged it, way too many for me. I'm mounting
the new valve under the floor on the driver's side and putting the power switch
in the hole where the old manual control rod poked through. Getting the rusted
screws loose holding the floor panels took several
days of spare time and liberal doses of Kroil®. I broke a couple and had
to drill out and re-thread the holes. 3/8" inch rubber fuel line will
connect the new valve to the the stock flared ends of the fuel lines, that will only
take six clamps, I can live with that. I'll shield the valve with a piece of
aluminum sheet.
(3) Speaking of heat, I worried about the two filters exposure to the heat generated
in that area by the exhaust. The exhaust
pipe is only about 2 or 3 inches from the tanks and the side of the transmission.
So I needed to put the fuel filters somewhere else. I decided to put them inside
the tanks. The existing brass screen filters in the tank
are not much good.
(4) I will wrap the fuel lines with fiberglass and aluminum and place an aluminum
shield between the transmission and the exhaust pipe. I believe that the location
of the exhaust has to induce gobs of heat into the transmission and fuel tanks/lines.
Once I got the tanks out it was clear
that something had to be done! On a long hard pull I can only imagine the heat
generated in this area. I also plan (another
project) to wrap the exhaust pipes and manifold/headers with a fiberglass type
wrap and install some aluminum sheeting to shield the gas tanks. I will also
put some aluminum foil type insulation on the tank surfaces that face the exhaust,
and also the same treatment for the transmission.
(5) I drained out the two gas tanks and found two different kinds of strainer/filters
on the fuel pickup tubes. One was a brass
screen that might filter out bigger chunks, the other was some sort of
filter paper that crumbled in my hand when I tried to remove it. I attempted
to replace it with a paper filter that I got at the local auto parts place.
I reamed the hole in the end of the small filter to fit over the pickup pipe
(13mm) and stuck it in the housing and slipped it over the pickup tube. It kept
falling apart because I had no glue available that would seal it back together.
(6) So I decided on a more permanent solution. As I intend to drain the tanks
annually to get any accumulated junk out, why not install a good quality replaceable
filter that could be changed at the same time? Good idea, says I. Now, how to
do it? First I pulled the pickup pipe and decided to use a metal filter screwed
in to the end of the pipe. The pipe would need shortened to compensate for the
filter length.
(7) After several trips to my local "Fast and Furious" parts store (seems the
punks in the loud Honda Civics have taken over the place) I found a steel filter
with a threaded end that would fit through the drain plug. Its a Deutsch FF201.
Hose fitting on one end, 1/2" inch threads on the other. The standpipe was too
thin for 1/2x20 threads (I tried) so I used a 3/8" inch hose barb. I trimmed
the barb end and filed the barbs down a little for a snug fit. Then I brazed
the hose barb into the pipe end. Here is what
my mockup looked like.
I tried to get steel hose barbs but couldn't locate any so I used brass. I just
had to watch how much heat I applied during the brazing process. After it cooled
I ran a 1/2" inch x 20 tap into the
female threads to clean them up and deepen them to allow the filter to seat
all the way up to the "O" ring. There was a slight bit of distortion
during the brazing. You can see here that the hose end of the filter will just
protrude into the depression at the bottom
of the tank. That way I won't lose any capacity. Here is a shot of the
compeleted joint with filter attached. I used a 1/2" inch "O" ring to seal
the filter against the finished pipe. I will also use teflon tape to insure
a good seal on the filter threads.
(8) And how do I propose to change the filter out? Simply by using a deep
well #22 mm socket . The tape was only
temporary. I was also pleasantly surprised at how clean
the tanks are inside, the only gunk I got out was some water and some slimy
purple stuff. I was amazed at how light the tanks are. The metal is not very thick at all. The outside has a few small rusty chips I'll coat with POR-15®
then paint the tanks with a good satin black paint which will help throw off
any additional heat. Maybe I'll even strip the transmission and paint it black
too. I remember all my air cooled engines were painted satin or flat black to
aid in cooling. The last guys to work on this Unimog sprayed a thick rubbery
"paint" on everything underneath to make it look good. Some of it covers rust
that I'm slowly fixing. See, more projects all the time.
Quick Reference Table (work in progress)
| 1. Here's where I tried to replace an old paper filter that was jammed into the housing in an attempt to replace the wadded filter. |
| 2. The filter housing would not stay together. |
| 3. Pollak motorized valve for two tanks. |
| 4. X More to follow in a few days...8-12-02 | 5.xx.Part list to follow in a few days...8/15/02 |
| 6.x I just looked at this page, can't believe this project has been sitting for over a year. It's now Sep 11, 2003. Too many things going on. I WILL finish it though... |
| 7.xx. |
| 8. XX |
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